Ro-Man Extension XJ-2, usually called simply Ro-Man, is the main antagonist of Phil Tucker's 1953 movie Robot Monster.
Ro-Man had a bipedal, gorilla-like body and a globular metallic head. It had a single round "eye," and a pair of long silver antennas. Ro-Man was capable of firing a Calcinator Death Ray to kill his enemies.
After wiping out nearly the entire human population with its Calcinator Death Ray, evil robot Ro-Man headed from its base on the moon to Earth to finish off the eight humans who had become resistant to its weapon. After killing four of the survivors, Ro-Man developed an illogical attraction to one of the remaining female survivors, and was unable to complete its mission.
This refusal to obey orders caused Ro-Man's alien overlord, the Great Guidance, to teleport to earth and destroy his former servant.